[SOLVED] Power supply short circuit protection

[Ogu Reginald]

I am building the power supply with short circuit protection whose diagram is on the attachment, but the problem is that the two resistors in the diagram are out of reach. Please can anyone help me with a better diagram or recommend a regulator IC (variabla 2V-about 35V) with in built short circuit protection and can handle upto 3Amps.

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Please I need replies urgent.

 

[BradtheRad]

The .7 and .07 ohms form a 10-to-1 resistor divider.

You can hook up low-ohm resistors in parallel to obtain these values.

To obtain .07 ohms using copper wire, it can be made from 8 inches of 30 AWG. Or 5 inches of 32 AWG. Etc.

The 0.7 ohm must carry 3 amps, so thin wire is not workable.

Do you have a 1 ohm, 5 or 10 watt type? (Probably rectangular sandstone?) Or 0.82 ohm?

If it's like one that I broke apart, you can gouge or ***** or break the coating (carefully) and expose a resistive wire inside.

It may not accept lead solder, but maybe you can use some kind of solder or welding, to attach your positive supply wire to the resistive element, 1/10 length from the end. That would be the same as what you need.

 

[tpetar]

Regulators short circuit protection circuits :

**broken link removed**

1.3 - 32 V / 5A Power Supply w/ Short Circuit Protection by LM338
http://www.circuit-projects.com/index2.php?option=com_content&task=view&id=92&pop=1&page=0&itemid=34
**broken link removed**

LM338K is my favorite voltage regulator its 5A and he is very powerfull, also have thermal protection and shortcircuit protection built-ined inside.

 

[Tahmid]

Switching regulators such as L4975 and L4977 have inbuilt current limiting circuitry.

 

[Ogu Reginald]

Can the regulators you mentioned above handle upto 3Amps?

 

[Tahmid]

Yes. L4975 is rated at 5A max. L4977 is rated at 7A max. You may also take a look at L4964, which is rated at 4A max.

You can find the circuits in the datasheets.

Hope this helps.
Tahmid.

 

[Ogu Reginald]

Can the regulators you mentioned above handle upto 3Amps?

 

[Tahmid]

Yes. I've answered: https://www.edaboard.com/threads/271682/#post1164392

L4975 is rated at 5A max. L4977 is rated at 7A max. You may also take a look at L4964, which is rated at 4A max.

You can find the circuits in the datasheets.

 

[tpetar]

Can the regulators you mentioned above handle upto 3Amps?

LM338K can handle 5A without problems.

LM338K have :
- Shortcircuit protection
- Thermal shutdown protection
- Current limiter


Trust me, I use LM338K sucessfully many years for charging Lead-Acid batteries.

 

[Ogu Reginald]

Thank you all for your contributions.

 

[tpetar]

Also there is 10A regulator L4970A can regulate in 5,1-40V range, and its switcher.

Thank you all for your contributions.

You are Welcome.

 

[Ogu Reginald]

What do you people mean by switching regulator.

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What do you people mean by switching regulator.

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What do you people mean by switching regulator.

 

[tpetar]

Switching regulator is ok, but request additional parts, and output ripple filters, also request more space (mainly from current/heatsink size. On lower current linear needs less space).



See post #8 and #12 in this thread:

https://www.edaboard.com/threads/269988/